Dactyloidae iOS initial commit

mobile/ios/Client/Frontend/Browser/ScreenshotHelper.swift

@@ -0,0 +1,59 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import Foundation
+
+/**
+ * Handles screenshots for a given tab, including pages with non-webview content.
+ */
+class ScreenshotHelper {
+    var viewIsVisible = false
+
+    fileprivate weak var controller: BrowserViewController?
+
+    init(controller: BrowserViewController) {
+        self.controller = controller
+    }
+
+    func takeScreenshot(_ tab: Tab) {
+        var screenshot: UIImage?
+
+        if let url = tab.url {
+            if url.isAboutHomeURL {
+                if let homePanel = controller?.homePanelController {
+                    screenshot = homePanel.view.screenshot(quality: UIConstants.ActiveScreenshotQuality)
+                }
+            } else {
+                let offset = CGPoint(x: 0, y: -(tab.webView?.scrollView.contentInset.top ?? 0))
+                screenshot = tab.webView?.screenshot(offset: offset, quality: UIConstants.ActiveScreenshotQuality)
+            }
+        }
+
+        tab.setScreenshot(screenshot)
+    }
+
+    /// Takes a screenshot after a small delay.
+    /// Trying to take a screenshot immediately after didFinishNavigation results in a screenshot
+    /// of the previous page, presumably due to an iOS bug. Adding a brief delay fixes this.
+    func takeDelayedScreenshot(_ tab: Tab) {
+        let time = DispatchTime.now() + Double(Int64(100 * NSEC_PER_MSEC)) / Double(NSEC_PER_SEC)
+        DispatchQueue.main.asyncAfter(deadline: time) {
+            // If the view controller isn't visible, the screenshot will be blank.
+            // Wait until the view controller is visible again to take the screenshot.
+            guard self.viewIsVisible else {
+                tab.pendingScreenshot = true
+                return
+            }
+
+            self.takeScreenshot(tab)
+        }
+    }
+
+    func takePendingScreenshots(_ tabs: [Tab]) {
+        for tab in tabs where tab.pendingScreenshot {
+            tab.pendingScreenshot = false
+            takeDelayedScreenshot(tab)
+        }
+    }
+}